The present invention relates generally to golf clubs and is particularly concerned with improved golf club shafts to provide increased control and ball flight distance.
Golf club shafts are generally elongate tubular members having a butt end for gripping by the player and a tip end to which a club head is secured. Various types of golf clubs are provided for different playing conditions, including woods and irons. Golf club woods, which may be of wood or metal, have a characteristic rounded head shape with a flat striking face. Iron heads are typically of solid molded metal having a wedge like shape and an angled ball striking face. An integral tubular hosel projects from the heel end of the face for securing the head to a shaft.
Various attempts have been made in the past to improve the ball striking characteristics of golf clubs, by redesign of the shaft or the head portion, or both. The swinging of a standard golf club will produce curvature of the shaft. During the golf swing, the principal objective is to exercise as much control as possible in order to make the ball fly as far as possible in the intended direction. When the shaft curves along its entire length, it is relatively difficult to maintain control and to transfer force from the handle to the club head effectively. Thus, attempts have been made in the past to control the flexing of a golf club shaft as the club is swung to impact the ball. In U.S. Pat. No. 2,457,177 of Reach, for example, a golf club is described which has a waist region of reduced diameter between its ends and enlarged diameter regions at both the head and handle or butt ends of the shaft, in order to stiffen the shaft in the vicinity of the club head, so that the head can engage the ball more accurately. The shaft is made up from a series of telescopically interconnected cylindrical sections of increasing and decreasing diameter. The smallest diameter section is closer to the head or tip end of the shaft than the handle or butt end of the shaft, and provides the point of greatest flexibility of the shaft.
U.S. Pat. No. 4,319,750 of Roy describes a golf shaft having a controlled flex zone at a predetermined location along its length. The shaft is fabricated from layers of different types of fiber materials each having a different modulus of elasticity. The materials are laminated so as to produce a flex point at the interface between the two materials. The butt portion of the shaft extending from the butt end is made more flexible than the remainder of the shaft extending to the tip or club end. The hinge point between the butt and tip portions of the shaft is closer to the butt end, and the shaft is relatively stiff between the hinge point and tip end of the shaft, and curves or flexes the most between the hinge point and butt of the shaft.